Back in 1983 Petrov made a decision that prevented a war that could have destroyed the planet. He was the duty officer at Russia’s main nuclear command center in September 1983 when the system indicated a nuclear missile attack was launched by the U.S. on Russia.

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The Soviet procedure manual was inflexible, and it demanded he notify his superiors of the attack immediately. But relying on his intuition, Petrov disobeyed. For almost five minutes, he stalled, holding his hotline phone in one hand and his intercom in the other, barking orders to his personnel to get back to their desks.

Then he made the decision that saved the world. Summoning up his firmest voice, he called his Kremlin liaison and said it was a false alarm. But today he admits, "I wasn’t 100 percent sure. Not even close to 100 percent".